Hook dog for sawmill carriages



June 22', 1926. 1,590,110

F. E. MARTIN HOOK DOG FOR SAWMILL CARRIAGES Original Filgd Nov. 25, 19212 Sheets-Sheet 1 gll i2 June 22 1926. 1,590,110

F. E. MARTIN HOOK DOG FOR SAWMILL CARRIAGES Original Filed Nov. 25.19212 Sheets-Sheet 2 Patented June 22, 1926.

UNITED STATES PATENT OFFICE.

FREDERICK E. MARTIN, OF WEED, CALIFORNIA, ASSIGNOB TO MARTIN AIR DOG ICOMPANY, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION 01 CALIFORNIA.

HOOK DOG FOR SAWMILL CABRIAGES.

Original application filed November 25, 1921, Serial No. 517,647.Divided and this application filed.

December 8, 1922.

This invention is directed to an improvement in hook dogs for saw millcarriages, wherein through the mounting and operation of the hook dog, amaterially im- 5 proved result is secured. This application issubstantially a division of my co-pending supplication filed November25, 1921, Serial No. 517,647. The invention may be substantially statedas directed to a hook dog so mounted and operated as to cause the spikeof the dog to follow'a path in operation which will cause said spike toengage any one ofa number of logs of difierent diameters atsubstantially the same relative location in each of said logs; to somount the :dog relative to its operating means that following theengagement of the hook dog with the log, the further and continuedmovement of the operating means causes the dog to move in asubstantially vlinear direction to draw the log towards the knee; tocushion the dog in its mounting to insure a proper penetrating effect ofthe dog without liability of displacement due to the shocks and jars ofsuch operation; and to so mount and operate the dog that the maximumpenetrating ower or blow of the dog is exerted on the argest log withwhich the dog may cooperate and gradually decreases throughout the fulloperative range of the dog.

In more specific detail, the hook dog structure of this inventioninvolves a frame mounted for swinging movement under suitable powermeans with the support for the frame forming a floating fulcrum. The dogis pivotally supported in the frame and compelled to move with the framethroughout the power stroke of the dog through a resilient connection,which when the dog engages the log, permits'a IBlEtlXG yielding betweenthe dog and frame to cause the further movement of the frame to move thedog in a linear direction to draw the log 5 toward the knee.

- Through the specific mounting of the frame on a floating fulcrum andapplying the power means beyond this fulcrum and normally between thefulcrum and the spike of the dog when the latter is in inoperativeposition, the powermeans acts initially between said operative end ofthe dog and the fulcrum to-exert the mazg'imum power effect Serial No.605,658.

on the dog, the point of application of the power to the framethereafter gradually approaching and moving beyond a line radial to thefloating fulcrum and normal to the line of travel of the power, with theeffect of operating the dog with the maximum power in the initial ortionof its stroke and graduall decreasing the power, through decrease o theleverage, throughout the remaining portion of the stroke.

The dog is held in desired relation to the frame for the power stroke bya spring interposed between the dog and frame and adustable as totension. This spring causes the dog to follow the frame as the latter isswung to thereby impart the arcuate movement to the dog, and when thespike of the dog penetrates the log, and is hence held against furthermovement, the spring yields to permit the frame to continue its swingingmovement without correspondingly swinging the dog. This further swingingmovement of the frame, by reason of the floating fulcrum, causes the dogto move in a linear direction with respect to the knee, and hence drawthe log toward theknee.

The invention is illustrated in the accompanying drawings, in which:

Fig. 1 is a perspective view of a hook dog constructed in accordancewith this invention and mounted in relation to the knee, the parts beingshown in normal or inoperative positions.

Fig. 2 is an elevation with the parts in operative position.

Fig. 3 1s a diagrammatic view showing the the path of travel of the dogthroughout its full stroke, this viewalso indicating other paths oftravel which the dog would follow dog and indicating by a dot and dashline like extension 6 projecting upwardly therefrom. To the upper end ofthis extension 6 is pivotally connected at 7 a frame 8, hereinafterreferred to as the dog frame. This frame comprises spaced identicalplates 9 secured together by bolts 10 and provided with intermediateedge spacing sections 11,

Y one of which forms a limiting abutment for the dog when in inoperativeposition.

A dog lever 12 having the usual terminal spike 13 is freely supported onthe pivot 7 between the plates 9, the edge spacing sections between theplates being omitted to permit the necessary play or movement of thedog. The dog and frame are designed to be operated by power means, and aconventional and convenient means for this purpose is here shown as acylinder 14 pivotally supported at the end remote from the dog frame bya pin 15 carried by'a yoke 16, and

is supported for rotation upon a pin 17 secured on a support extendingfrom the knee 2. In utilizing this form of operating means, the cylinderis provided with ports 18 and 19 adjacent the respective ends thereoffor the admission of air or steam under pressure to operate in thedesired direction a piston 20 slidably arranged in said cylinder andhaving its piston rod 21 connected to the pivot pin 7. The dog frame isfurther supported for pivotal movement through the medium of a rod 22,pivotally connected to said frame on a pin 23 passing through the platesof the frame at a point normally in rear of the pivot 7, as shown inFig. 3. The opposite end of the rod 22 is supported upon the pivotalmounting of the cylinder, as shown. The dog frame is provided with aseries of holes 24 to provide for the adjustable connection of the rod22 therewith, for a purpose which will laterlappear.

It is to be particularly noted that the dog is mounted for free play onthe pivot pin 7,

' except for the means to be now described,

and it is through the provision of such means as a yielding resilientconnection that an important advantage of the structure results. Thisdog frame and dog connecting means comprises a yoke 25 embracing oneedge of the dog frame, which frame is interiorly open, and within theframe and in advance of the pivot 7 said yoke is connected to the doglever 12 at 26. A rod 27 is pivotally connected to one edge of the dogframe and extends through the yoke 25 beyond the frame, said rod beingprovided with a coil spring 28 encircling the rod and bearing at one endon the yoke 25; The opposite end of the spring is adjustably confined bya washer 29 slidable on the rod 27 and held in position to adjustablytension the spring by a nut 30 engaging the threaded free end of the rod27.

change 0 operative positions of the parts, it will be noted that thepivots 7 and 23 are substantially in line at right angles to the face ofthe knee, with the pivot 7 in advance of the pivot 23 due of course tothe full projection of the piston rod 21. In this posi tion, the spring28 exerts a suflicient pressure upon the yoke 25 to hold the hook doglever 12 in contact with the abutment indicated at 11. As pressure isadmitted to the cylinder to operate the hook dog, for example, throughport 18, the iston rod is moving the pivot 7 rearward y on dotted line2, having for its fulcrum the pin 4. The spring 28 however, stillmaintains the hook dog lever in contact with the abutment 11 of the dogframe with the result that said lever and therefore the penetratingspike 13 at the free-end of the lever is compelled to follow themovement of the dog frame until, for example, the said s ike engages andpenetrates the log. During this operation however, the spike of the doglever does not follow a true arcuate ath, nor is the power communicatedto the rec end of such lever the same throughout its path of movementnotwithstanding uniformity in the operating ower admitted to thecylinder 14.

W ien the spike takes it bite into the log, assuming that the log is notup against the knees, the piston 20 continues its movement and the frame8 continues its rocking motion. The spike end of the dog lever however,cannot now follow the swinging movement of the frame, as it is engagedin a log, and consetjuently the spring 28 yields to permit a re ativemovement of the dog lever and frame, and as in this continued furthermovement of the frame, the pivot pin 7 is necessarily movin toward the clinder 14, along the dotte line 2; the 0g lever and therefore the logwill be moved toward the knee with substantially a linear movement, andthus the log will be drawn toward and into contact with the knee. F urthermore, from the relative arrangement of the mounting and partsconnected therewith, it will be apparent that in the normal orinoperative position, the line of application of power to pivot 7 passesvery close to the pivot 23 and the movement of the do being unresistedby the work starts witli great rapidity, giving penetrative force to,

the dog; the power acting substantially transverse to the dog bar orparallel to its dog or tooth. As the dog approaches the log, the line ofpower and the pivot 23 separate, increasing the power arm of the leverconstituted by the frame 8 and the dog bar until the dog has reachedabout the position of engagement with a maximum sized log. If the dostrikes a log at this point, such leverage, in the absence of anresistance up to this point, has not material 1y lessened the speed ofthe dog and it pone "the dog is slowed down in entering a large sizedlog, the gradually increased leverage acts to force the do into andpowerfully hold the'log. n the other hand, with lesser sized logs andvarying according to thesize of the log, the line of application of theforce to pivot 7 again approaches the pivot 23 and shortens the leverageof the power, while the dog having a longer travel before striking thelog, more of the momentum of its original starting motion is lost as itpasses through the point of maximum increase in the power leverage, andthe subsequent change of leverage is not sufliciently rapid greatly toquicken up again the speed of the dog, so that the dog strikes the logwith-less force while the decreasing leverage applies less finalpenetrative force to the dog. It will thus be apparent that by reason ofthe unresisted initial rapidity in the movement of the dog, the velocityand consequently the penetrative force of the tooth are at theirmaximums throughout the initial movement, and if in the particularstructure the maximum sized log with which the dog is to cooperate willbe engaged by the tooth during the gradual increase of the leveragereferred to above, it will be apparent that for the maximum sized log,the penetrative force of the tooth is also at its maximum. As

- the power leverage shortens thereafter, that movement,

is, in moving the dog to cooperate with logs of less than the maximumsize, it will be apparent that the dog will strike the log with less andless power as the diameter of the log decreases to the minimum sized logto be handled by the particular apparatus, and therefore the penetrativeforce of the dog decreases correspondingly. Large logs will thus beengaged with great penetrativ force, while smaller logs will be en gagedwith less penetrative force, the purpose of which is obvious.

In Fig. '3, there is diagrammatically illustrated the describedoperation of the dog. In this figure, a indicates logs of differentdiameters supported on the carriage, and 7) indicates the path of travelof the point of the spike of the hook dog when mounted on the floatingfulcrum structure herein described. In orderthat the irregularity of thearc of this path of movement may be graphically appreciated, there isalso illustrated two additional circular paths of indicated at 0 and d.The centers of these respective paths of movement are indicated at e andf, which corre-.

spond to the pivots 23 and 7, were these pivotsstationary and the dogcaused to operate about either as a center. This illustration emphasizesthe hereinbefore stated fact that the spike of the dog first describesan abrupt curve. for the inibial'part of its path and then movesinwardlly while still travelling in a curved path and downwardly,gradually approaching the knee and receding from the saw line. The paths0 and (I however, which are true arcs from fixed centers, move graduallyfrom the knee and toward the saw line, and were either of these pathsthe true path of the dog spike, it is apparent that smaller logs wouldbe so engaged by the .dog spike asto permit little if any of the log toextend beyond such dog for saw operation. I

, \Vhen the spike strikes a log, the spring 28 will also serve as acushion to take the blow, and in the further movement of the frame, ashereinbeforeset forth, wherein the spring is tensioned to permit therelatively independent movement of the frame and dog, the springoperates by such increased tension to assist and gradually compel thespike to penetrate the log, and of more importance insures that thespike will be held in the log against casual displacement due to jarsor. vibrations.

While the floating fulcrum 23 and the brace associated therewith, offersa resistance to the movement of the pivotal support 7 under the powermeans, and while this arrangement is essential to produce the desiredpath of movement to the dog, and the additional advantages referred to,yet when the dog spike contacts with the log and the spring is thereuponfurther compressed, such spring provides an additional resistance to thepressure means, to thereby prevent a too I rapid or violent movement ofthe log toward the knee.

It will be apparent that by the provision of the holes 24 in the dogframe, the floating fulcrum 23, that is, the connection of the rod- 22to the frame, may be adiusted; and that through this adjustment the pathof movement of the dog may be varied with relation to the face of theknee. That is to say,

the adjustable connection of the floating fulcrum with the dog framewilldetermine the distance of the'path of movement of the spike of thedog beyond the face of the knee.

Claims:

1. In combination, a frame, a floating fulcrum for the frame, a dogmounted in the frame beyond such floating fulcrum. and a power meansconnected to the frame and moving the dog as a lever on such floatingfulcrum, said power means acting initially to impart maximum speed tothe dog undera continuously increasing power leverage. the leveragebeing thereafter gradually shortened to reduce the power movement of thedog, the floating fulcrum under the action of the power means causingthe dog to travel in a curved path'in the nature of a cycloid. I 3

2. In combination, a frame, a floating fullcrum for the frame, adogmounted in the frame beyond such floating fulcrum, and a power meansconnected to the frame and moving the dog as a lever on such floatingfulcrum, said power means acting initially to impart maximum speed tothe dog under a continuously increasing power leverage, the leveragebeing thereafter gradually shortened to reduce the power movement offrame and movable the dog, and means permitting the frame to swing onthe floating fulcrum under the action of the power means after the doghas engaged a log.

3. In combination, a floating fulcrum, a support therefor, a framemounted on the floating fulcrum, means for moving the frame on saidfulcrum, a dog pivoted on the fulcrum, a spring between the frame anddog to insure that both the frame and the dog will move together on the"floating fulcrum until the dog contacts with a log, said spring servingthereafter to hold the dog in contact with the log while permitting ayielding movementzbetween the frame and dog to allow the frame tocontinue to move.

4. In combination, a floating fulcrum, a support therefor, a framemounted on the floating fulcrum, a dog pivoted on the frame, means tocause both the frame and the dog to move together on and with thefloating fulcrum until the dog contacts with a log and thereafter holdthe dog in contact with the log while the frame continues to move.

5. A saw mill carriage dog and operating means, comprising a floatingfulcrum, and means for moving the dog about such fulcrum inproportionate relation to cause the dog to engage substantially thecenter of the top of a log regardless of substantial variation in thesize of the log, and then draw the log towards the knee.

6. A saw mill carriage dog and operating means therefor, including afloating fulcrum, and means for moving the dog about such fulcrum andsimultaneously moving the fulcrum in such proportionate relation as tocause the dog to engage substantially the center of the top of a logregardless of substantial variation in the size of the log.

7 A dog structure for saw mill carriages, comprising a rocking support,a swinging member mounted on said support, a dog pivotally connected tothe member, and a spring between the member and the dog to cause saiddog to tend to move with the member until the dog strikes a log andpermit the member to continue to swing relative to the support after thedog strikes alog to thereby draw the log toward the knee, and means foroperating the member.

8. A dog structure for saw mill carriages, comprising a frame, means forpivotally mounting the frame, a dog pivoted to the herewith, a springbetween the frame and the dog to cause said dog to tend to move with theframe and allow an independent swinging movement of the frame after thedog strikes a log, and means connected to the pivot between the dog andframe for operating the dog structure. 9. A dog for. saw mill carriages,comprising two elements pivoted together, yielding means which aloneholds the elements together in working relation and, permits independentmovement of said elements when the dog contacts with a log,- and meansfor swinging the dog.

10. A dogging means for saw mill carr ages, comprising a pivoted frame,a dog pivotally mounted in the frame to one side the ivot of the frame,a string between the rame and the dog, means to adjust the tension ofthe spring to determine the extent of movement of the frame before thedog rocks in the frame after contacting with a log, and means forswinging the frame and creating a pull on the dog.

l1. A dogging means for saw mill carriages, comprising a pivoted dog,means for mounting the dog to cause same to travel in a curved path andwhen resistance is met in a substantially straight path, including aspring, and means to-adjust the tension of the spring to determine theextent of the straight path movement of the dog, and means for operatingthe dog.

12. A saw mill carriage dog, means for mounting the dog to cause its totravel in a curved path in the nature of a cycloid until a log isencountered and thereafter move toward the knee, and means for operatingthe dog. I

13. A swinging hook dog, a floating fulcrum therefor, means for swingingsaid dog on said fulcrum and simultaneously moving the fulcrum, andcushion means brought into action when and after the dog contacts with alog to resist the dog-swinging action of the operating means.

14. A swinging hook dog, a floating fulcrum therefor, means for swingingsaid dog on said fulcrum and simultaneously moving the fulcrum, andcushion means amociated with and movable with the hook dog and broughtinto action when and after the dog contacts with a log to resist thedog-swinging action of the operating means.

15. A hook dog, an operating means therefor, and a mounting for saidhook dog directly actuated by said operating means, said mountingcausing the operative end of the dog to follow a path of an irregulararc with initial maximum velocit and minimum power, and thereafter withgradual decreasing velocity, the power gradually increasing to apredetermined point in the movement of the dog and, thereafterdecreaslng.

operative end- 16. A- hook dog, a power means therefor, and a mountingfor said dog directly actuated by said power means, said mounting beingsupported on a floating fulcrum and the power connection to the mountingbeing normally between such floating fulcrum and the operative end ofthe dog, said power connection moving around the floating fulcrum in adirection from the operative end of the dog to thereby reduce theleverage length of the dog and cause the operative end of the dog totravel in an are which ,constantly approaches the fulcrum.

17. A hook dog, an o for, a mounting in w 'ch the dog is supported anddirectly actuated by the operating means, said moun providing for twomovements of the dog, one toward the log and the other substantiallytransverse-the first, and additional means for normally connecting thedog and mounting for unit movement, said means permitting relativemovements of the dog and mounting when the movement of the dogisresisted as by engagement with a log.

18. A hook dog, an operating means therefor, a mounting in which the dogis sup ported and directly actuated by the operating means, saidmounting providing for two movements of the dog, one toward the log andthe other substantially transverse the first, and additional means fornormallyconnecting the dog and mounting for unit movement, said meanspermitting increasingly resisted relative movements of the dog' andmounting when the movement of the dog is resisted as by engagement witha log.

19. A hook dog, an operating means therefor, a mounting in which the dogis supported and directly actuated by the operating means, said mountingproviding for two movements of the dog, one toward the log and the othersubstantially transverse the first, and spring means for connecting thedog and mounting for unit movement in the absence of resistance to dogmovement.

20 A hock dog, an operating means therefor, a mounting in which the dogis supported and directly actuated by the operating means, said mountingproviding for two movements of the dog, one toward the log and the othersubstantially transverse the first, and spring means for connecting thedog and mounting for unit movement, said means permitting relativemovements of the dog and mounting when the dog engages a log.

21. A hook dog, an operating means therefor, a mounting in which the dogis supported and directly actuated by the operating means, said mountingproviding for two movements of the dog, one toward the log and the othersubstantially transverse the first, and spring means for connecting thedog and mounting for unit movement, said rating theremeans permittingincreasingly resisted relative movements of the dog and mounting whenthe do engages a log.

22..A hoo 1 dog, an operating means therefor, a mountin in w ich the dogis supported and direct y actuated by the operating means, said mountingproviding for two movements of the dog, one toward the log and the othersubstantially transverse the first, and spring means for'connecting thedog and mounting for unit movement, said means permittin of the dog andmounting when the dog engages a log, and also serving to assist inholding the dog in engagement with the log during such relative-movement.-

23. A hook dog, an o crating means therefor, a mounting in ating means,said mounting providing for two movements of the dog, one toward the logand the other substantially transverse the first, and spring means forconnecting relative movements ch the dog is supported and directlyactuated by the, operthe dog and mounting for unit movement,

holding the dogin engagement with the log with increasing effect duringsuch relative movement.

24. A hook dog, an operating means therefor, a mounting in which the dogis supported and directly actuated by the operating means, said mountingproviding for two movements of'the dog, onetoward the log and the othersubstantially transverse the first, and a spring serving to connect themounting and dog for unit movement until the dog strikes the log, saidspring cushioning the dog impact and thereafter permitting relativemovement between the dog and mounting.

25. In combination, a saw-mill carriage, a knee, a cylinder pivotallymounted on the knee, a rocking frame on the knee, a piston and rodpivoted to the rocking frame and operable in the cylinder, a swingingframe mounted on the pivot which connects the rocking frame and thepiston rod, a hook dog mounted on said pivotal connection, springactuated means engaging the hook dog to .hold same 'in engagingposition, a floating fulcrum between the swinging frame and the knee,and means for controlling fluid pressure to the cylinder, whereby whenpressure is admitted to the cylinder, the pivotal connection and thefloating fulcrum will swing the swinging frame and move the hook dog ina curved path and subsequently pull the hook do Inn . means connected tothe dog on one side the l the spring permittin tuated the dog willfulcrum, and a spring on the opposite side of the fulcrum connected tothe dog, whereby when the pressure 0 erated means is acfiirst rock in acurved path to engage a log and subsequently exert a pull on the logandsimultaneously compress the spring, the sprin permitting of the pull onthe log after tie dog engages the 10 28. In combination, a knee and dogfor saw mill carriages, an arm pivoted at one end to the knee and at itsopposite end to form a floating fulcrum for the dog, a spring interposedbetween the floating fulcrum and the dog, and means connected to the dogfor first rocking the same on the floating fulcrum to move the dog in acurved path to engage a log and after such engagement to move thefloating fulcrum and dog to pull the 10 toward the knee,

the spring permitting o the pull on the log after the dog engages thelog.

29. In combination, a dog for a saw mill carriage, a floating fulcrumfor the same, means on one side of the floating fulcrum for operatin thedog, and spring means on the other si e of the floating fulcrum to actas a resistance to the dog when operated to engage a lo whereby the dogis first moved in a curve path and subsequently pulled, of the operatingmeans imparting the ual movement to the hook.

30. In combination, a dog for a saw mill carriage, a floating fulcrumfor the same,

means for operating the dog, and a floating spring pivoted to the dog,whereby when the dog is actuated the dog will first be rocked in acurved path and subsequently bodily pulled, the s rin permitting of thelog bemg pulled a r ing engaged by the dog.

31. In combination, a dog for saw mill carriages, means for mounting thesame, including a floating fulcrum, arranged to permit first a rockingmovement of the dog about the fulcrum while the latter is floating andwhen such floating movement is interrupted by enga 'ement of the dogwith a log, converts such rocking movement into a floating movement onlyof the fulcrum to exert a'pull on the log, and power means so. ap liedas to cause a movement of the dog an floating fulcrum as permitted bythe sprin 32. A swinging dog, a floating fulcrum therefor, means forswinging said dog on said fulcrum and simultaneously moving the fulcrum,and means for resisting the movement of the floating fulcrum.

33. A swinging dog, a floating fulcrum therefor, means for swinging saiddog on said fulcrum and simultaneously moving the fulcrum, and springmeans for resisting the movement of the floating fulcrum after .the docontacts with a log.

34. swinging dog, a floating fulcrum therefor, means for swinging saiddog on said fulcrum and simultaneously moving the fulcrum, and meansinaugurated through and following movement of the dog after the lattercontacts with a log to resist movement of said floating fulcrum.

35. A swinging dog, a floating fulcrum therefor, means for swinging saiddog on said fulcrum and simultaneously movin the fulcrum, and meansinaugurated with increasing effect through and following a predeterminedmovement of the dog to resist movement of said fioatin fulcrum.

In testimony whereof I afix my signature. k

FREDERICK E. MARTIN.

and aspring

